1. Technical Field of the Invention
The present invention relates to an apparatus for washing and disinfecting an endoscope comprising a dilution tank into which a chemical, which is stored in a chemical bottle, and dilution water, which dilutes the chemical to a predetermined concentration to be used for disinfecting an endoscope, are charged.
2. Related Art
In recent years, endoscopes are widely used in medical and industrial fields. The endoscope used in the medical field comprises an elongated flexible insertion tube having an insertion duct for a therapeutic device (hereinafter, referred to as a “therapeutic device channel”). Inserting the insertion tube into a body cavity of an object (i.e., patient) being examined allows an operator to view organs in the body cavity and perform various treatments by using the therapeutic device inserted into the therapeutic device channel, as needed.
The endoscope in the medical field is used by being inserted into a body cavity, especially for the purpose of examination and treatment. Therefore, after use, the endoscope should be washed and disinfected for reuse. The method using an endoscope washer-disinfector is known as one method for washing and disinfecting a used endoscope.
The endoscope washer-disinfector automatically washes, disinfects, rinses, and drains (hereinafter, referred to as a “washing and disinfecting process”) the used endoscope only by setting the endoscope in a washing bath. In this case, not only an outer surface of the endoscope but also a plurality of ducts (channels) such as an air duct, a water duct, and the therapeutic device channel therein are washed and disinfected.
In the meantime, when the endoscope washer-disinfector described above disinfects an endoscope, a disinfectant solution, for example, a chemical comprising a base solution such as peracetic acid and a buffer solution is used. The chemical is generally used by being diluted with dilution water such as tap water to a predetermined concentration. To ensure effective disinfection of the endoscope, it is required that adjustment of the concentration of dilution and control of humidity are properly performed.
In addition, when the diluted chemical is rapidly heated, it loses its efficacy. Therefore, when using a chemical having higher practical temperature, the dilution water is generally heated in a heating tank before it is charged into a dilution tank.
Furthermore, the conventional apparatus described above comprises two chemical bottles storing a base solution and a buffer solution having the volumes for disinfecting an endoscope one or more times, respectively. The base solution and the buffer solution in the respective chemical bottles are charged into the dilution tank. Thereafter, a predetermined volume of the dilution water is charged into the dilution tank through a dilution water inlet connected to the dilution tank to adjust the chemicals in a proper concentration. Note that the chemical properly diluted as described above is supplied from the dilution tank to the used endoscope by using a known means, thereby disinfecting the endoscope.
As described above, the chemical bottles store the base solution and the buffer solution for disinfecting the endoscopes several times. The base solution and the buffer solution are supplied from the respective chemical bottles to the dilution tank through respective supplying means, whose driving sources are pumps, provided in respective supply ducts connecting the chemical bottles to the dilution tank.
In addition, the volumes of the base solution and the buffer solution supplied to the dilution tank are generally controlled with water level sensors or the like disposed in the dilution tank or the respective chemical bottles. By way of example, Japan Pat. Appln. KOKAI Publication No. 2000-287924 discloses an endoscope washer-disinfector in which a plurality of level sensors are disposed in a tank. The level sensors detect the volume of a chemical stored in the tank in stages in response to the level of the chemical in the tank to control the volume of the chemical to be supplied.
In addition, an apparatus is known in which a base solution and a buffer solution are supplied from respective chemical bottles, in which the base solution and the buffer solution are stored for one-time disinfection of an endoscope, to a dilution tank. In this apparatus, a technique is well known for charging all the base solution and the buffer solution stored in the chemical bottles into the dilution tank using the weight of the base solution and the buffer solution.
However, in the endoscope washer-disinfector disclosed in the Japan Pat. Appln. KOKAI Publication No. 2000-287924, when the chemicals are diluted in the dilution tank, the volume of the chemicals to be used may be small with respect to the volume of the dilution tank. In such the case, that is, in a case where the chemicals are single-use, and the volume of the chemicals to be supplied is small, variation of the level in the dilution tank is small after the chemicals are supplied. Therefore, even when a plurality of level sensors are used, precise control of the volume of the chemicals to be supplied is difficult.
In addition, a configuration is known in which sensors detecting the level of a chemical are disposed inside a chemical bottle. In this case, replacement of the chemical bottle is complicated, while the chemical bottle becomes expensive. Furthermore, a technique is conceived in which the volume of chemicals to be supplied is controlled with flow sensors disposed in respective supply ducts connecting chemical bottles to a dilution tank. However, the flow sensor is expensive in general.